Thermally-controlled photonic structure

Abstract

In some implementations, a thermally-controlled photonic structure may include a suspended region that is suspended over a substrate; a plurality of bridge elements connected to the suspended region and configured to suspend the suspended region over the substrate, where a plurality of openings are defined between the plurality of bridge elements; and at least one heater element having a modulated width disposed on the suspended region. The at least one heater element having the modulated width may include at least one section of a greater width and at least one section of a lesser width. The at least one section of the greater width may be in alignment with an opening of the plurality of openings and the at least one section of the lesser width may be in alignment with a bridge element of the plurality of bridge elements.

What is claimed is: 
     
       1. A thermally-controlled mirror structure, comprising:
 an optical waveguide region suspended over a substrate,
 wherein the optical waveguide region includes a grating for reflecting light; 
 
 a plurality of bridge elements connected to the optical waveguide region and configured to suspend the optical waveguide region over the substrate; and 
 at least one heater element disposed on the optical waveguide region,
 wherein the at least one heater element is structured and arranged relative to the plurality of bridge elements to compensate for heat dissipation along the plurality of bridge elements and to control a temperature profile along the grating, 
 wherein the at least one heater element includes at least one concave section, and 
 wherein the at least one heater element is structured and arranged relative to the plurality of bridge elements such that the at least one concave section is in alignment with a bridge element of the plurality of bridge elements. 
 
 
     
     
       2. The thermally-controlled mirror structure of  claim 1 , wherein the at least one heater element comprises a resistive heater. 
     
     
       3. The thermally-controlled mirror structure of  claim 1 , wherein the temperature profile is uniform. 
     
     
       4. The thermally-controlled mirror structure of  claim 1 , wherein, to compensate for a self-heating effect caused by a light source on the grating, the plurality of bridge elements and the at least one heater element are structured and arranged relative to one another such that:
 lengths of the plurality of bridge elements decrease in a direction of light propagation from the light source, and 
 the at least one concave section includes a plurality of concave sections that increase in depth in the direction of light propagation from the light source. 
 
     
     
       5. The thermally-controlled mirror structure of  claim 1 , wherein a first section of the thermally-controlled mirror structure is closer to a light source than a second section of the thermally-controlled mirror structure, and
 wherein the first section has a first thermal tuning efficiency that is lower than a second thermal tuning efficiency of the second section. 
 
     
     
       6. The thermally-controlled mirror structure of  claim 1 , wherein the at least one heater element is further structured and arranged relative to a light source to compensate for a self-heating effect caused by the light source on the grating. 
     
     
       7. The thermally-controlled mirror structure of  claim 1 , wherein the at least one heater element is positioned above or at a side of a waveguide ridge of the optical waveguide region. 
     
     
       8. The thermally-controlled mirror structure of  claim 1 , wherein the at least one heater element comprises a first heater element and a second heater element, and
 wherein the first heater element and the second heater element are positioned at opposite sides of a waveguide ridge of the optical waveguide region. 
 
     
     
       9. A thermally-controlled photonic structure, comprising:
 a suspended region that is suspended over a substrate; 
 a plurality of bridge elements connected to the suspended region and configured to suspend the suspended region over the substrate; and 
 at least one heater element disposed on the suspended region,
 wherein the at least one heater element is structured and arranged relative to the plurality of bridge elements to compensate for heat dissipation along the plurality of bridge elements and to control a temperature profile along the suspended region, 
 wherein the at least one heater element includes at least one concave section, and 
 wherein the at least one heater element is structured and arranged relative to the plurality of bridge elements such that the at least one concave section is in alignment with a bridge element of the plurality of bridge elements. 
 
 
     
     
       10. The thermally-controlled photonic structure of  claim 9 , wherein the at least one heater element has rectangular modulation. 
     
     
       11. The thermally-controlled photonic structure of  claim 9 , wherein the at least one heater element has triangular modulation. 
     
     
       12. The thermally-controlled photonic structure of  claim 9 , wherein the at least one heater element has sinusoidal modulation. 
     
     
       13. The thermally-controlled photonic structure of  claim 9 , wherein the at least one concave section has a length that is equal to a length of the bridge element. 
     
     
       14. The thermally-controlled photonic structure of  claim 9 , wherein lengths of the plurality of bridge elements decrease in a direction of light propagation of the thermally-controlled photonic structure, and
 wherein the at least one concave section includes a plurality of concave sections that increase in depth in the direction of light propagation. 
 
     
     
       15. A tunable laser, comprising:
 a thermally-controlled mirror structure, comprising:
 an optical waveguide region suspended over a substrate,
 wherein the optical waveguide region includes a grating for reflecting light; 
 
 a plurality of bridge elements connected to the optical waveguide region and configured to suspend the optical waveguide region over the substrate; and 
 at least one heater element disposed on the optical waveguide region,
 wherein the at least one heater element is structured and arranged relative to the plurality of bridge elements to compensate for heat dissipation along the plurality of bridge elements and to control a temperature profile along the grating, 
 wherein the at least one heater element includes at least one concave section, and 
 wherein the at least one heater element is structured and arranged relative to the plurality of bridge elements such that the at least one concave section is in alignment with a bridge element of the plurality of bridge elements. 
 
 
 
     
     
       16. The tunable laser of  claim 15 , wherein the at least one heater element comprises a first heater element and a second heater element, and
 wherein the first heater element and the second heater element are positioned at opposite sides of a waveguide ridge of the optical waveguide region. 
 
     
     
       17. The tunable laser of  claim 15 , wherein, to compensate for a self-heating effect caused by a light source on the grating:
 lengths of the plurality of bridge elements decrease in a direction of light propagation from the light source, and 
 the at least one concave section includes a plurality of concave sections that increase in depth in the direction of light propagation from the light source. 
 
     
     
       18. The thermally-controlled mirror structure of  claim 1 , wherein the at least one concave section has a length that is equal to a length of the bridge element. 
     
     
       19. The thermally-controlled photonic structure of  claim 9 , wherein the at least one heater element comprises a resistive heater. 
     
     
       20. The tunable laser of  claim 15 , wherein the at least one heater element comprises a resistive heater.